Files
Wino-Mail/Wino.Calendar.ViewModels/CalendarPageViewModel.cs

455 lines
18 KiB
C#

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using CommunityToolkit.Diagnostics;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Messaging;
using Wino.Calendar.ViewModels.Data;
using Wino.Calendar.ViewModels.Interfaces;
using Wino.Core.Domain.Collections;
using Wino.Core.Domain.Enums;
using Wino.Core.Domain.Interfaces;
using Wino.Core.Domain.Models.Calendar;
using Wino.Core.Domain.Models.Calendar.CalendarTypeStrategies;
using Wino.Core.Domain.Models.Navigation;
using Wino.Core.ViewModels;
using Wino.Messaging.Client.Calendar;
namespace Wino.Calendar.ViewModels
{
public partial class CalendarPageViewModel : CalendarBaseViewModel,
IRecipient<LoadCalendarMessage>,
IRecipient<CalendarSettingsUpdatedMessage>
{
[ObservableProperty]
private ObservableRangeCollection<DayRangeRenderModel> _dayRanges = [];
[ObservableProperty]
private int _selectedDateRangeIndex;
[ObservableProperty]
private DayRangeRenderModel _selectedDayRange;
[ObservableProperty]
private bool _isCalendarEnabled = true;
// TODO: Get rid of some of the items if we have too many.
private const int maxDayRangeSize = 10;
private readonly ICalendarService _calendarService;
private readonly IAccountCalendarStateService _accountCalendarStateService;
private readonly IPreferencesService _preferencesService;
// Store latest rendered options.
private CalendarDisplayType _currentDisplayType;
private int _displayDayCount;
private SemaphoreSlim _calendarLoadingSemaphore = new(1);
private bool isLoadMoreBlocked = false;
private CalendarSettings _currentSettings = null;
public IStatePersistanceService StatePersistanceService { get; }
public CalendarPageViewModel(IStatePersistanceService statePersistanceService,
ICalendarService calendarService,
IAccountCalendarStateService accountCalendarStateService,
IPreferencesService preferencesService)
{
StatePersistanceService = statePersistanceService;
_calendarService = calendarService;
_accountCalendarStateService = accountCalendarStateService;
_preferencesService = preferencesService;
}
// TODO: Replace when calendar settings are updated.
// Should be a field ideally.
private BaseCalendarTypeDrawingStrategy GetDrawingStrategy(CalendarDisplayType displayType)
{
return displayType switch
{
CalendarDisplayType.Day => new DayCalendarDrawingStrategy(_currentSettings),
CalendarDisplayType.Week => new WeekCalendarDrawingStrategy(_currentSettings),
_ => throw new NotImplementedException(),
};
}
public override void OnNavigatedFrom(NavigationMode mode, object parameters)
{
// Do not call base method because that will unregister messenger recipient.
// This is a singleton view model and should not be unregistered.
}
public override void OnNavigatedTo(NavigationMode mode, object parameters)
{
base.OnNavigatedTo(mode, parameters);
_currentSettings = _preferencesService.GetCurrentCalendarSettings();
}
partial void OnIsCalendarEnabledChanging(bool oldValue, bool newValue) => Messenger.Send(new CalendarEnableStatusChangedMessage(newValue));
private bool ShouldResetDayRanges(LoadCalendarMessage message)
{
if (message.ForceRedraw) return true;
// Never reset if the initiative is from the app.
if (message.CalendarInitInitiative == CalendarInitInitiative.App) return false;
// 1. Display type is different.
// 2. Day display count is different.
// 3. Display date is not in the visible range.
var loadedRange = GetLoadedDateRange();
if (loadedRange == null) return false;
return
(_currentDisplayType != StatePersistanceService.CalendarDisplayType ||
_displayDayCount != StatePersistanceService.DayDisplayCount ||
!(message.DisplayDate >= loadedRange.StartDate && message.DisplayDate <= loadedRange.EndDate));
}
public async void Receive(LoadCalendarMessage message)
{
await _calendarLoadingSemaphore.WaitAsync();
try
{
await ExecuteUIThread(() => IsCalendarEnabled = false);
if (ShouldResetDayRanges(message))
{
DayRanges.Clear();
Debug.WriteLine("Will reset day ranges.");
}
else if (ShouldScrollToItem(message))
{
// Scroll to the selected date.
Messenger.Send(new ScrollToDateMessage(message.DisplayDate));
Debug.WriteLine("Scrolling to selected date.");
return;
}
// This will replace the whole collection because the user initiated a new render.
await RenderDatesAsync(message.CalendarInitInitiative,
message.DisplayDate,
CalendarLoadDirection.Replace);
}
catch (Exception ex)
{
Debugger.Break();
}
finally
{
_calendarLoadingSemaphore.Release();
await ExecuteUIThread(() => IsCalendarEnabled = true);
}
}
private DateRange GetLoadedDateRange()
{
if (DayRanges.Count == 0) return null;
var minimumLoadedDate = DayRanges[0].CalendarRenderOptions.DateRange.StartDate;
var maximumLoadedDate = DayRanges[DayRanges.Count - 1].CalendarRenderOptions.DateRange.EndDate;
return new DateRange(minimumLoadedDate, maximumLoadedDate);
}
private async Task RenderDatesAsync(CalendarInitInitiative calendarInitInitiative,
DateTime? loadingDisplayDate = null,
CalendarLoadDirection calendarLoadDirection = CalendarLoadDirection.Replace)
{
// This is the part we arrange the flip view calendar logic.
/* Loading for a month of the selected date is fine.
* If the selected date is in the loaded range, we'll just change the selected flip index to scroll.
* If the selected date is not in the loaded range:
* 1. Detect the direction of the scroll.
* 2. Load the next month.
* 3. Replace existing month with the new month.
*/
// 2 things are important: How many items should 1 flip have, and, where we should start loading?
// User initiated renders must always have a date to start with.
if (calendarInitInitiative == CalendarInitInitiative.User) Guard.IsNotNull(loadingDisplayDate, nameof(loadingDisplayDate));
var strategy = GetDrawingStrategy(StatePersistanceService.CalendarDisplayType);
var displayDate = loadingDisplayDate.GetValueOrDefault();
// How many days should be placed in 1 flip view item?
int eachFlipItemCount = strategy.GetRenderDayCount(displayDate, StatePersistanceService.DayDisplayCount);
DateRange flipLoadRange = null;
var initializedDateRange = GetLoadedDateRange();
if (calendarInitInitiative == CalendarInitInitiative.User || initializedDateRange == null)
{
flipLoadRange = strategy.GetRenderDateRange(displayDate, StatePersistanceService.DayDisplayCount);
}
else
{
// App is trying to load.
// This should be based on direction. We'll load the next or previous range.
// DisplayDate is either the start or end date of the current visible range.
if (calendarLoadDirection == CalendarLoadDirection.Previous)
{
flipLoadRange = strategy.GetPreviousDateRange(initializedDateRange, StatePersistanceService.DayDisplayCount);
}
else
{
flipLoadRange = strategy.GetNextDateRange(initializedDateRange, StatePersistanceService.DayDisplayCount);
}
}
// Create day ranges for each flip item until we reach the total days to load.
int totalFlipItemCount = (int)Math.Ceiling((double)flipLoadRange.TotalDays / eachFlipItemCount);
List<DayRangeRenderModel> renderModels = new();
for (int i = 0; i < totalFlipItemCount; i++)
{
var startDate = flipLoadRange.StartDate.AddDays(i * eachFlipItemCount);
var endDate = startDate.AddDays(eachFlipItemCount);
var range = new DateRange(startDate, endDate);
var renderOptions = new CalendarRenderOptions(range, _currentSettings);
renderModels.Add(new DayRangeRenderModel(renderOptions));
}
// Dates are loaded. Now load the events for them.
foreach (var renderModel in renderModels)
{
await InitializeCalendarEventsAsync(renderModel).ConfigureAwait(false);
}
CalendarLoadDirection animationDirection = calendarLoadDirection;
bool removeCurrent = calendarLoadDirection == CalendarLoadDirection.Replace;
if (calendarLoadDirection == CalendarLoadDirection.Replace)
{
// New date ranges are being replaced.
// We must preserve existing selection if any, add the items before/after the current one, remove the current one.
// This will make sure the new dates are animated in the correct direction.
isLoadMoreBlocked = true;
// Remove all other dates except this one.
await ExecuteUIThread(() =>
{
DayRanges.RemoveRange(DayRanges.Where(a => a != SelectedDayRange).ToList());
});
animationDirection = displayDate <= SelectedDayRange?.CalendarRenderOptions.DateRange.StartDate ?
CalendarLoadDirection.Previous : CalendarLoadDirection.Next;
}
if (animationDirection == CalendarLoadDirection.Next)
{
await ExecuteUIThread(() =>
{
foreach (var item in renderModels)
{
DayRanges.Add(item);
}
});
}
else if (animationDirection == CalendarLoadDirection.Previous)
{
// Wait for the animation to finish.
// Otherwise it somehow shutters a little, which is annoying.
if (!removeCurrent) await Task.Delay(350);
// Insert each render model in reverse order.
for (int i = renderModels.Count - 1; i >= 0; i--)
{
await ExecuteUIThread(() =>
{
DayRanges.Insert(0, renderModels[i]);
});
}
}
Debug.WriteLine($"Flip count: ({DayRanges.Count})");
foreach (var item in DayRanges)
{
Debug.WriteLine($"- {item.CalendarRenderOptions.DateRange.ToString()}");
}
if (removeCurrent)
{
await ExecuteUIThread(() =>
{
DayRanges.Remove(SelectedDayRange);
});
}
// TODO...
// await TryConsolidateItemsAsync();
isLoadMoreBlocked = false;
// Only scroll if the render is initiated by user.
// Otherwise we'll scroll to the app rendered invisible date range.
if (calendarInitInitiative == CalendarInitInitiative.User)
{
// Save the current settings for the page for later comparison.
_currentDisplayType = StatePersistanceService.CalendarDisplayType;
_displayDayCount = StatePersistanceService.DayDisplayCount;
Messenger.Send(new ScrollToDateMessage(displayDate));
}
}
private async Task InitializeCalendarEventsAsync(DayRangeRenderModel dayRangeRenderModel)
{
// Load for each selected calendar from the state.
var checkedCalendarViewModels = _accountCalendarStateService.GroupedAccountCalendars
.SelectMany(a => a.AccountCalendars)
.Where(b => b.IsChecked);
foreach (var calendarViewModel in checkedCalendarViewModels)
{
// Check all the events for the given date range and calendar.
// Then find the day representation for all the events returned, and add to the collection.
var events = await _calendarService.GetCalendarEventsAsync(calendarViewModel,
dayRangeRenderModel.Period.Start,
dayRangeRenderModel.Period.End)
.ConfigureAwait(false);
foreach (var calendarItem in events)
{
var calendarDayModel = dayRangeRenderModel.CalendarDays.FirstOrDefault(a => a.RepresentingDate.Date == calendarItem.StartTime.Date);
if (calendarDayModel == null) continue;
var calendarItemViewModel = new CalendarItemViewModel(calendarItem);
await ExecuteUIThread(() =>
{
// TODO: EventsCollection should not take CalendarItem, but CalendarItemViewModel.
// Enforce it later on.
calendarDayModel.EventsCollection.Add(calendarItemViewModel);
});
}
}
}
private async Task TryConsolidateItemsAsync()
{
// Check if trimming is necessary
if (DayRanges.Count > maxDayRangeSize)
{
Debug.WriteLine("Trimming items.");
isLoadMoreBlocked = true;
var removeCount = DayRanges.Count - maxDayRangeSize;
await Task.Delay(500);
// Right shifted, remove from the start.
if (SelectedDateRangeIndex > DayRanges.Count / 2)
{
DayRanges.RemoveRange(DayRanges.Take(removeCount).ToList());
}
else
{
// Left shifted, remove from the end.
DayRanges.RemoveRange(DayRanges.Skip(DayRanges.Count - removeCount).Take(removeCount));
}
SelectedDateRangeIndex = DayRanges.IndexOf(SelectedDayRange);
}
}
private bool ShouldScrollToItem(LoadCalendarMessage message)
{
// Never scroll if the initiative is from the app.
if (message.CalendarInitInitiative == CalendarInitInitiative.App) return false;
// Nothing to scroll.
if (DayRanges.Count == 0) return false;
var initializedDateRange = GetLoadedDateRange();
if (initializedDateRange == null) return false;
var selectedDate = message.DisplayDate;
return selectedDate >= initializedDateRange.StartDate && selectedDate <= initializedDateRange.EndDate;
}
partial void OnSelectedDayRangeChanged(DayRangeRenderModel value)
{
if (DayRanges.Count == 0 || SelectedDateRangeIndex < 0) return;
var selectedRange = DayRanges[SelectedDateRangeIndex];
Messenger.Send(new VisibleDateRangeChangedMessage(new DateRange(selectedRange.Period.Start, selectedRange.Period.End)));
if (isLoadMoreBlocked) return;
// Send the loading message initiated by the app.
if (SelectedDateRangeIndex == DayRanges.Count - 1)
{
// Load next, starting from the end date.
_ = LoadMoreAsync(CalendarLoadDirection.Next);
}
else if (SelectedDateRangeIndex == 0)
{
// Load previous, starting from the start date.
_ = LoadMoreAsync(CalendarLoadDirection.Previous);
}
}
private async Task LoadMoreAsync(CalendarLoadDirection direction)
{
Debug.WriteLine($"Loading {direction} items.");
try
{
await _calendarLoadingSemaphore.WaitAsync();
await RenderDatesAsync(CalendarInitInitiative.App, calendarLoadDirection: direction);
}
catch (Exception)
{
Debugger.Break();
}
finally
{
_calendarLoadingSemaphore.Release();
}
}
public void Receive(CalendarSettingsUpdatedMessage message)
{
_currentSettings = _preferencesService.GetCurrentCalendarSettings();
// TODO: This might need throttling due to slider in the settings page for hour height.
// or make sure the slider does not update on each tick but on focus lost.
Messenger.Send(new LoadCalendarMessage(DateTime.UtcNow.Date, CalendarInitInitiative.App, true));
}
}
}